The subject matter herein relates generally to antennas for wireless devices.
Wireless devices or wireless communication devices have use in many applications including telecommunications, computers and other applications. Examples of wireless devices include mobile phones, tablets, notebook computers, laptop computers, desktop computers, handsets, personal digital assistants (PDAs), a wireless access point (AP) such as a WiFi router, a base station in a wireless network, a wireless communication USB dongle or card (e.g., PCI Express card or PCMCIA card) for computers, and other devices. The wireless devices include antennas that allow for wireless communication with the device. Several antenna characteristics are usually considered in selecting an antenna for a wireless device, including the size, voltage standing wave ratio (VSWR), gain, bandwidth, and the radiation pattern of the antenna.
Known antennas for wireless devices have several disadvantages, such as limited bandwidth, large size, interference from a user's hand and/or head, and the like. Some known antennas for wireless devices address some of the antenna problems using composite right and left handed (CRLH) metamaterials for the antennas. For example, U.S. Pat. No. 7,764,232 to Achour, the subject matter of which is incorporated by reference in its entirety, describes antennas using CRLH metamaterial structures. Such antennas have expanded bandwidth to cover broader frequency ranges, but still run into bandwidth limitations.
It is desirable with systems today to use wireless devices that operate in multiple frequency bands simultaneously or to use wireless devices that effectively operate in specific radio bands and are able to remotely select such bands for different networks. Known antennas for wireless devices are not able to effectively address these needs, at least in part due to bandwidth limitations.
A need remains for an antenna that effectively operates in a broad frequency bandwidth while having a small physical antenna size.